Yeah, it kinda sounds like you might have overdone it. Can you tell that the pain has subsided any since you've stopped knitting for a while?

Often soreness will go away after a few days; however, if the pain hasn't lessened any, you might want to high thee to a doctor to make sure there's nothing wrong there!

When I push myself too hard either typing or knitting and/or crocheting (or any combination of those), my wrists and hands get really sore. I often hold them under a pulsing blast of water in the shower, moving it up and down my wrists and on the palms of my hands. That helps a lot, as does massage--especially if you can get someone else to do the massaging. Other than that, it requires taking a long break to let it heal and then not going at the knitting/typing/crocheting quite so hard--especially without lots of breaks in between sessions.

It's sure frustrating, I know. Perhaps you can give your friend the blanket still on the needles (so she can see it) and then finish it at a more leisurely pace.